Many medical procedures or treatments require internal access into the patient's body. Surgical access into the body may sometimes involve a working channel for the insertion of tools for the injection or removal of materials into or out of a desired site within the body. In a majority of cases, an access device, such as a cannula, is used to provide this working channel. For example, in many surgical bone treatments, a portal to inject directly into the bone is employed. This portal is conventionally created with a standard trocar and cannula. Generally, before or during the process of removing the trocar, the surgeon will manually drive, either by pushing, twisting, or a combination of both, the cannula into the bone. The residing cannula provides a clear path into the bone for effecting treatment.
Problems arise, however, when the cannula or trocar must overcome a large resistive force as it is being inserted into the bone. When the force is finally overcome, the cannula or trocar plunges too far forward. Another problem is created during bone treatments when manually twisting the cannula into bone creates an oval cavity in the cortical bone and negates the seal. These issues can lead to damage of cancellous/cortical bone, or an incomplete fill with extravasations.
It would therefore be desirable to provide the necessary tools and instruments to allow a powered tool to drive an access device such as a cannula, pin, needle, or other known injection or extraction portal, directly into the patient's body. It would also be desirable to provide surgical access instruments and systems that allow the surgeon with more control to create the working channel for medical treatments. It would be even more desirable to provide these instruments and systems with better depth control, alignment control, and ease of use.